KRAUSNICK, GERMANY - FEBRUARY 15: Visitors ride innertubes down a waterslide at the Tropical Islands indoor resort on February 15, 2013 in Krausnick, Germany. Located on the site of a former Soviet military air base, the resort occupies a hangar built originally to house airships designed to haul long-distance cargo. Tropical Islands opened to the public in 2004 and offers visitors a tropical getaway complete with exotic flora and fauna, a beach, lagoon, restaurants, water slide, evening shows, sauna, adventure park and overnights stays ranging from rudimentary to luxury. The hangar, which is 360 metres long, 210 metres wide and 107 metres high, is tall enough to enclose the Statue of Liberty. (Photo by Sean Gallup/Getty Images)